Defending Against Additive Attacks with Maximal Errors in Watermarking Relational Databases

Recently, several database watermarking techniques have been developed to fight against database piracy. In watermarking, a database owner’s identification information is embedded into a database such that proof of ownership can be established by detecting the information in pirated data. However, most watermarking systems are vulnerable to the severe threat of additive attacks and this threat has not been studied formally. In an additive attack, a pirate inserts an additional watermark such that the proof of ownership becomes ambiguous. In this paper, we present an effective approach to defending against additive attacks. Our strategy is to raise the errors introduced during watermark insertion to a predetermined threshold such that any additive attack would introduce more errors than the threshold. Exceeding the error threshold means that the pirated data is less useful or less competitive; thus, the owner does not need to claim ownership for such pirated data.